This invention relates generally to the art of butterfly valves, and more specifically, to apparatus and a method for reconstituting skewed-axis butteryfly valves.
Skewed-axis butterfly valves of the type with which this invention is used, depicted in FIGS. 1-3, are in common use throughout industry and are often used on ships.
Heretofore, some discs of these valves have been made with replaceable O-rings in perimeter grooves so that the O-rings could be periodically replaced without replacing the whole discs. However, many extremely corrosive applications of such valves do not allow the use of perimeter O-rings but rather require that the discs be made totally of metal. As in the case of valves with O-rings, the metal discs also corrode at their perimeters. Heretofore, it has been possible to throw away the corroded discs of such valves and replace them with new discs. However, the manufacturers of such discs often do not stock them so they are often difficult to purchase in a timely manner. Further, such butterfly-valve discs are extremely expensive. Thus, some users of skewed-axis butterfly valves have repaired the discs by welding metal about their outer perimeters and then filing the outer perimeters to form new, appropriately-shaped perimeter surfaces. Although some money can be saved using this procedure, the procedure is time consuming and inexact. To date there is no relatively easy, exact and economical way to reconstitute these all-metal, skewed-axis, butterfly valve discs. Thus, it is an object of this invention to provide apparatus and a method for reconstituting all-metal skewed-axis butterfly valve discs which is economical, fast, exact and relatively easy to perform.
It is a further object of this invention to provide such a method of reconstituting skewed-axis butterfly valves which allows the butterfly-valve discs thereof to be quickly, and smoothly, worked on a lathe.